I just finished redoing the walls in the basement.I put in all new electrical boxes in the walls running the conduit to the ceiling Where can I find out how to wire the outlets in the wall and how many outlets can be on a 15 amp breaker.I want to run the wiring directly to the box

Several months ago, one of several recessed ceiling fixtures in my basement would light for several minutes and then shut off and then come back on several minutes later and repeated this while switched on. Eventually I replaced the switch, and it worked fine for several weeks. But a week or so ago it began blinking again, and now it won't light at all. I replaced the bulb of course. An upstairs room and several closets are on the same circuit breaker and work fine. This fixture is 20 years old and has worked fine until now. Other fixtures in the basement ceiling are also working fine, although this one sits at the foot of the stairs, so it gets used more often. This is a plasterboard type ceiling rather than made of panels, and I see no way to get the fixture out for inspection or replacement. A sticker inside the fixture reads, "Thermally protected fixture. Light blinking indicates improper lamp size or insulation too close to fixture. Light Life." Is there maybe some kind of "switch" in the fixture itself that may have gone bad? It's the same bulb type I've used for 20 years without problem. Any help would be appreciated.